Drilling bit



Nov. 9, 1954 I H. E. ROBERTS DRILLING BIT Filed Aug. 1, 1952 Harry E. Roberts I INVENTOR.

. BY @mwflam United States Patent DRILLING BIT Harry E. Roberts, Clare, Mich. Application August 1, 1952, Serial No. 302,107 3 Claims. (Cl. 255-61) The present invention relates to certain new and useful improvements in drilling tools and has to do with a novelly constructed head and a battery of novelly constructed cutting bits assembled on the head to cooperate in serving a common end; namely, effective penetration and satisfactory boring of a hole in varying kinds of formations.

Briefly summarized, the invention comprises a head having axial means at its upper end for attachment to a drill collar, drill rod or the like, said head including a body cylindrical in cross-section and provided in its peripheral surface with vertical grooves forming keyways, the latter closed at their upper ends and opening at their lower ends through the bottom of said body, said grooves being dove-tailed in cross-section and arranged at equidistant circumferentially spaced places around the circumference of said body, an insertable and removable cutter bit for each groove, each bit having a dove-tailed keying rib fitting into its respective groove and abutting the closed upper end of the groove and also having a cutter blade which is polygonal in cross-section, said cutter blade radiating beyond said peripheral surface, the outermost surface of said cutter blade being bevelled and providing a vertical cutting edge along the leading face of the blade, and means removably securing said bit in its groove.

One object of the invention is to provide the aforementioned head whose body portion is provided in its peripheral surface with the stated vertical grooves or keyways, the bottom of the head being provided with grooves functioning as additional keyways and the latter radiating from the center of the body and communicating at their outer ends with their respective vertical grooves, whereby to provide an especially grooved body to accommodate cutting bits which are L-shaped in configuration, the inward surfaces of the long and short portion of the bits having keying ribs which provide for satisfactory mounting of the bits on the body and which facilitate the steps of inserting and removing the bits.

Another object of the invention has to do with the stated L-shaped bits whose vertical portions constitute cutting blades and whose horizontal portions constitute cutting feet, each blade and each foot having coinciding cutting edges produced by bevelling the outward surfaces of said blade and foot complements.

Then, too, novelty is predicated on incorporating or embedding a plurality of block-like hard metal inserts in the respective blade and foot portions of each bit, these inserts registering with the cutting edges, whereby the over-all bit performs more satisfactorily because of its ability to penetrate, cut and shift the surfaces encountered.

Further novelty is predicated on a series or battery of L-shaped bits having the structural features mentioned wherein the sizes of the inserts for each bit vary and wherein there is also a variation in the sizes of the inserts of the bits compared one to the other, whereby the long inserts cut trenches in the formation and the shorter inserts chip the formation and so that the over-all drill operates faster flian other similarly constructed drills and also lasts longer. And, too, bits having the shape mentioned and provided with inserts properly installed insure the hole will be kept in gage during the drilling operation.

What is more, novelty is predicated on L-shaped bits fitting into grooves provided therefor in the body portion of a drill head wherein the foot portions of the respective bits are of varying lengths, at least one foot extending from the axial center of the bottom of the body and the others terminating in spaced relation radially from said center and being of varying lengths to provide a staggered arrangement for more satisfactorily reaming during the first cutting or penetration step.

Other objects, features and advantages will become more readily apparent from the following description and the accompanying sheet of drawings.

In the sheet of drawings wherein like numerals are employed to designate like parts or elements throughout the views:

Figure 1 is a view in section and elevation showing the complete ready-to-use drilling tool constructed in accordance with the principles of the present invention.

Figure 2 is a bottom plan view of the same.

Figure 3 is a horizontal section on the line 3-3 of Figure 1 looking in the direction of the arrows.

Figure 4 is a perspective view of one of the attachable and detachable cutting bits.

The head is denoted by the numeral 6 and is characterized by a centrally bored upper portion 8 the bore of which is denoted at 10. The upper end portion is reduced and screwthreaded as at 12 so that it may be connected to drill collars, a drill pipe, drill rods, tubing or any other kind of a drill stem. The lower or main body portion is denoted by the cylindrical in cross-section. It has a fiat, circular bottom 16. The bores 18 are water passages which communicate with the bore 10. The outer peripheral surface of the body is provided at equidistant circumferentially spaced points with vertical grooves forming keyways and these are denoted by the numerals 20 and they are dovetailed in cross-section and open at the lower ends through the body and are closed at their upper ends. The lower ends have communication with the radial grooves 22 in the bottom. These grooves also serve as keyways and they are rectangular in cross-section.

This arrangement of grooves serves to accommodate the readily attachable and detachable cutting bits. Each bit is denoted, as a unit, by the numeral 24. Each bit is essentially L-shaped in configuration or side elevation. It therefore has a vertical portion and a horizontal portion and the vertical portion, which is long, constitutes a cutting blade which is denoted by the numeral 26. This is essentially rectangular in cross-section and the outer surface thereof is chamfered or beveled to provide a vertical cutter edge 28. This bevel is transverse while there is a longitudinal bevel at 30 which reduces the upper cross-section of the blade. On the inner side of the blade is a dove-tailed keying rib 32 which fits into the correspondingly shaped keyway in the body portion. The numeral 34 designates holes for screws 36 which aid in securing the bit in its correct place. The horizontal short portion may be conveniently described as a foot and it is denoted by the numeral 38 and it has a rectangular keying rib 40 to fit into one of the grooves of keyways 22. The numerals 42 and 44 respectively designate the hard metal inserts which coincide with the cutting edges. The cutting edge of the foot which is formed by bevelling the under side of the foot is denoted by the numeral 46 and it coincides with the edge 28 and the inserts coincide with the respective edges. These inserts may be of suitable material, for example Carboloy. It will be noticed that the inserts 42 and 44 vary in sizes and are all essentially rectangular in cross-section. Also the inserts on the cooperating bits vary with each other and also with the insert on the companion bit. All these have to be properly planned and Worked out according to the particular job which is to be done. By properly sizing and staggering inserts, effective trenching and chipping of the formation is insured.

As beforementioned and as shown in Figure 2, the feet on the respective cutting bits vary in length and at least one foot extends from the axial center outwardly beyond the periphery of the body and others terminate at their inner ends short of the central axial point. The variation of lengths is worked out to provide a staggered arrangement which insures more elfective penetration and reaming. The keys 32 fit into the vertical keyways or grooves 20 while the keys 40 fit into the grooves 22, as is obvious.

numeral 14 and this is It is thought that persons skilled in the art to which the invention relates will be able toobtainaclear understanding of the invention after considering the description in connection with the drawings. Therefore, a more lengthy description is regarded as unnecessary.

.Minor changes in the-shape, size and arrangement of details coming within the field of'invention claimedmay be resorted to in actual practice, if desired.

Having described the invention, what is claimed as new is:

l. .A drilling tool of the class described comprising a head having axial means at its upper :end for attachment to a .drill collar, drill rod or the like,.said head including a body-cylindrical incross-section-andprovided in its peripheral surface with vertical grooves forming keyways, the latter closed attheirzupper endsand opening at their lower ends through the bottom of said body, said grooves being dovetailed in cross-section and arranged at equidistant circumferentially spaced places around the circumference of said body, the bottom of said body being essentiallyfflat :and having radial horizontal grooves matching and aligned with the respective vertical grooves, and a .plurality of complemental L-shaped cutting'bitsihaving vertical and horizontal portions :removably fitted into their respective vertical and horizontal grooves, said'horizontal radial grooves being rectangular in cross-section, the vertical and horizontal portions of said bits having keying ribs keyed in said grooves and said ribs corresponding in'cross-section with their respective keying grooves.

2. A drilling tool of the class described comprising a head having axial means at its upper end for attachment to a drill collar, ardrill'rod or the like, said head including a body cylindricalin cross-section and provided in its peripheral surface with vertical grooves formingkeyways, the latter closed at their upper ends and opening at their lower ends through the bottom of said'body, said grooves being dovetailed in cross-section and arranged at equidistant 'circumferentially 'spacedplaces around the circumference of said body, the bottom of said body being primarily fiat and having radial horizontal grooves matching and aligned with the respective vertical grooves, and a plurality of complemental L-shaped cutting bits having vertical and horizontal portions removably fitted into their respective vertical and horizontal grooves, the horizontal portions of the respective bits being of varying lengths.

3. A drillingtool of the class described comprising a head having axial means at its upper end for attachment to a drill collar, a drill rod or the like, said head including a body cylindrical in cross-section and provided in its peripheral surface with vertical grooves forming keyways, the latter closed at their upper ends and opening at their lower ends through the bottom of said body, said grooves being dovetailed in cross-section and arranged at equidistant circnrnferentially spaced places around the circumference of said body, the bottom of said body being essentially flat andhaving radial-horizontal grooves matching and aligned with the respective vertical grooves, the'horizontal portions of the respective bits being'of varying lengths, at least one horizontal portion reaching from the axial center of the body portion and the remaining. horizontal portions being staggered and having their inner ends progressively spaced from said axial center.

References Cited inthe file of this patent UNITED STATES PATENTS Number Name Date 1,510,871 Swaim Oct. 7, 1924 1,645,962 Mills Oct. 18, 1927 1,950,101 Dixon Mar. 6, 1934 2,057,209 Schlumpf Oct. 13, 1936 

